1. Field of the Invention
The present invention relates to a structure of seat back of a vehicle seat, wherein the seat back is provided, at the back side thereof, with a back board which can serve as a load-carrying platform or cargo loading area in a vehicle.
2. Description of Prior Art
Among various kinds of seats, there is known a fold-down rear seat of the type allowing its seat back to be foldable onto its seat cushion, thereby allowing the back side of the seat back to be transformed into a load-carrying platform area in a cabin section or a cargo loading section in a vehicle cabin, as found in a recreational vehicle, a mini-van, a station wagon, a small-sized vehicle, or the like.
In most cases, this sort of fold-down rear seat is provided with a back board at the back side thereof. One typical example of such back board is known from the Japanese Laid-Open Patent Publication No. 2000-125796, according to which, one piece of robust flat panel having a high rigidity is disclosed.
Normally, a cabin or a cargo loading section in vehicle, which can accommodate the fold-down rear seat of the foregoing type, requires formation of a storage space in the floor so as to allow both of seat cushion and seat back of the seat to be stored in that storage space, such that, when the seat back is folded down onto the seat cushion, the back side of the seat back is set in registry with the upper surface of the floor. In view of such structural requirement, it is desirable that a whole of the seat, or, particularly the seat back, should be made small in thickness. Particularly, the same goes for a small-sized vehicle.
To meet this demand, it would be necessary to reduce the thickness of foam padding (i.e. a cushion body) in the seat back so as to provide a relatively thin seat back. However, when it comes to attaching the foregoing conventional rigid back board to the back side of such thin seat back, a degree of elasticity of the padding will be limited by the rigid back board, resulting in a poor cushioning effect of the padding. In other words, a passenger resting on the seat back will feel, at his or her back, the hardness of the back board, due to the reduced thickness of the padding in the seat back, with the result that a comfortable seating touch is not attained.